Automatic case stacker



Filed NOV. 9, 1961 W. S. RAYNOR AUTOMATIC CASE STAGKER 6 Sheets-Sheet 1T. HT??? "7 Um? I TT [9 l4 i. w; U 56 55 -i I 4 1:? l 7L A2 mm m. 5 1

4 15 if T Li 9?? I8 |0 |3 '2 FIG I r if? 4 40 T Ac. SOURCE PB. START PB.STOP LS! LS3b AC! OUT F METERING FIG /\/AC| |N CIRCUIT R28 LS4 AczeuT xFINGER @RTR Raf R LS5 2b AC2 IN PCS [I] HOIST R20 CONTROL CIRCUIT I LS7clRculT N j AFTER STACK DISCHARGE STACK KR L CIRCUIT DISCHARGE LS6 R eLS8 w INVENTOR. WARREN s. RAYNOR BY RB. DISCH. M 514M; 6. 4, a/ME,

A TTORNE Y5 INVENTOR.

Feb. 15, 1966 w. s. RAYNOR 3,235,100

AUTOMATIC CASE STACKER @Qfi? 1 m WARREN s. RAYNOR g 2 Q g 2M4, Km; 5 4,$150 g ATTORNEYS.

Feb. 15, 1966 w. s. RAYNOR AUTOMATIC CASE STACKER 6 Sheets-Sheet 5 FiledNov. 9, 1961 Fl G 4 INVENTOR. WARREN s. RAYNOR A TTORNEY5- Feb. 15, 1966w. s. RAYNOR AUTOMATIC CASE STACKER 6 Sheets-Sheet 4 Filed Nov. 9, 1961FIG. 5

INVENTOR. WARREN S. RAYNOR A TTORNEYS.

Feb. 15,- 1966 w. s. RAYNOR 3,235,100

AUTOMATIC CASE STACKER Filed Nov. 9, 1961 6 Sheets-Sheet 5 W1; mi FIG? I'1 9 l f f E INVENTOR. i J W WARREN s. RAYNOR A TTORNE Y5.

Feb. 15, 1966 w. s. RAYNOR AUTOMATIC CASE STACKER 6 Sheets-Sheet 6 FIG.9

Filed Nov. 9. 1961 FIG. IO

INVENTOR. WARREN S. RAYNOR BY h 5 Sdfu iz," flma ATTORNEYS.

United States Patent 3,235,100 AUTOMATIC CASE STACKER Warren S. Raynor,Port Hope, Ontario, Canada, assignor to Mathews Conveyor Company,Ellwood City, Pa., a corporation of Pennsylvania Filed Nov. 9, 1961.Ser. No. 151,244 9 Claims. (Cl. 214-6) This invention relates to acarton, box or case stacking device adapted to be used with a linearconveyor for the placement of individually received cartons in stackedtiers and for the release of these stacked cartons to pass via theconveyer to a loading station or other means for storage or transport.

More particularly the invention relates to an understacking device withmeans for controlling automatically the infeed of cartons, the stackingoperation, the limiting height, and the discharge of the stacked cartonsautomatically in a device which is adaptable to use with a linearconveyer already installed and without the .use of a pit or otherspecial equipment arrangements. The device of this invention isessentially .a self-contained unit which is separable from the conveyerand isportable. At the same time it is adapatable for use with anautomatic palletizer or load distribution control mechanism such thatthe stacking operation automatically terminates if stacked cartons donot pass from the stacker.

Previous devices for the general purpose of this invention have beengenerally quite complicated and expensive to manufacture and tomaintain. They have generally occupied considerably more space than isdesirable and have required permanent installation either with a pit, anoverhead line or other permanent structure in the platform area wherethe operation takes place. Likewise, adjustments for dififerent sizepackages or cartons have been difiicult or impossible with prior devicesfor this purpose. It has generally not been possible to move such astacker from one location to another or from one conveyer to another,whereas the present invention is intended to permit this flexibility ofuse. Likewise, most such devices have not been entirely automatic intheir operation or have been subject to clogging or malfunctioning inthe absence of an attendant. The disadvantages of prior devices includethe rather large amount of machinery necessary to accomplish the purposewith a consequently high cost for such devices-and the necessity forlarge operating space to permit their use.

It is an object of this invention to provide a conveyer stackermechanism completely automatic in operation, so

long as cartons are supplied thereto and stacked cartons are removedfrom its delivery area. 7

Another object of the invention is to provide a stacker which may beemployed with already existing conveyers .which is movable from onelocation to another.

A further object is to provide a stacking mechanism which is simple inoperation, requiring few parts to wear or become maladjusted and tonevertheless supply.ac-

curately stacked cartons at a high rateof stacking.

A still further object of the invention is to provide a case stackersuitable for use with cases ofcardboard material wherein the operatingfingers and arms are prevented from damaging the cartons inasmuch asheavy arms need not be ratchet operated by, or rubbed against, thecartons during stacking.

A still further object .of the invention is to provide a stackingmechanism which is cheaper to manufacture and maintain and whichprovides a more accurate vertical alignment of cartons stacked in tiers.

Other objects and contemplated advantages will be evident as thedescription proceeds by reference to the drawings in which:

3,235,100 Patented Feb. 15, 1966 FIG. 1 is a diagrammatic plan view ofthe stacking mechanism together with a portion of the infeed and outfeedconveyer showing infeed control;

FIG. 2 is a diagrammatic e'levational view taken lateral- 1y of theconveyer and showing infeed of a carton and outfeed of a stack ofcartons;

FIG. 3 is a fragmentary sectional view taken as indicated by the line 33of FIG. 1;

FIG. 4 is a fragmentary vertical sectional view taken 'in the planeindicated by line 44 of FIG. 3;

FIG. 5 is a fragmentary sectional view taken in the transversehorizontal plane at line 55 of FIG. 3;

FIG. 6 is a generally sectional view taken along line 6-6 of FIG. 5;

FIG. 7 is a fragmentary sectional view showing an inside elevation takenalongline 7-7 of FIG. 4 to illustrate sequence control elements of theoperation;

FIG. 8 is an elevational view of the sequence control anddrivingmechanism taken in the direction ofline 88 of FIG. 7;

FIG. 9 is a plan view partly in section showing the infeed controlmechanism in relation to a carton passing along the conveyers;

FIG. 10 is an elevation largely in section taken along line 1610 of FIG.9;

FIG. 11 is a pictorial perspective view showing positional locations ofswitches adapted to control and actu- 'ate a sequence of eventsproducing finished stacks of cartons; and

FIG. 12 is a schematic electrical control diagram showing the operationof the mechanisms and switches.

There is shown generally in FIGS. 1 and 2 a linear conveyer 10 supportedin any convenient way as by posts 11 resting on the floor or othersupporting structure. A conveyer consists of a horizontally bottomedchannel 12 extending generally through thestacker and into a loading orpalletizing area not shown in detail. This channel will normally besupplied with side panels 13 which are adjustable to accommodatepackages of different widths. These panels may be employed both at theinfeed and exit ends of the conveyer, but are not shown except asmodified for the purpose of this invention which employs 'one such panel13 at one side of the conveyer, and at the other side of-the conveyerthere is an offset panel 14 adjustable to accept between it and panel 13a carton of the desired width. The panel 14 overrides a portion of thechannel 12 and forces cartons moving therealong laterally into contactor near contact with panel 13. Panel 13 terminates at or near atransverse abutment 15, having parallel portion 15' therebeyond, laterto be described. Panel 14 terminates one carton length toward the infeedend of the conveyer from the position of the abutment 15 such that acarton passing along the channel and striking the abutment 15 can beolfset by meanslater to be described into the channel beyond thetermination of the panel 14 and is there held in the channel by means ofa further panel portion 16 which may extend on the same side of theconveyer beyond the stacking mechanism. Any carton or case inserted inthe infeed section of the channel 12 from other conveyer sections, orotherwise deposited therein by an operator, is fed along the channel bymeans of a belt or chain arrangement. shown at 17 which is supportedslightly above the level of the channel bottom so as to contact eachcarton placed thereon. The bearing surface of the chain or belt 17 ispreferably slightly elevated from the channel, or of moderately highfriction material to assure positive transport of the cartons, yetpermitting cartons to be temporarily arrested thereon. It may, ofcourse, be a continuous moving belt or a chain structure with segmentedblocks serving as the bearing surface. In either case this belt travelsthrough substantially the center line of the channel, particularly atthe position beyond the stacker mechanism. At the infeed end of theconveyer ahead of the stacking mechanism the conveyer belt is showncloser to one edge of a carton carried therealong than to the other edgeby virtue of the fact that the panel 14 is inserted and adjusted partway across the channel 12 so as to form an offset portion of the channelbetween members 14 and 13, and there is at the entrance to the stackermechanism a broadened portion of the channel between the abutment 15'and side panel 16 of the channel. Any carton traveling along thechannel, therefore, comes against the abutment 15, and the opposite rearcorner thereof, as shown in FIG. 1, is free to rotate about the abutment15 only until it contacts wall 16. The forward corner of the carton isstopped against the abutment and cannot proceed therebeyond untilfurther controls are operated, as will later be described. The spacebetween panel 16 and the abutment 15' is adjusted to just exceed thewidth of a carton such that an arrested carton cannot pass the barrier15 into the stacking mechanism. A displaced carton, shown at 18 in FIGS.1 and 9, is shown repositioned for transport at 18 in FIG. 9 by dottedoutline. A further arriving carton is shown at 19 in FIG. 1.

Means for operating and controlling the conveyer belt do not form a partof this invention and are not shown, except that drive rollers are shownat 21 and 22. It will be unnecessary to further describe the conveyersince this may be of any well-known type having a moving belt centrallyextending therealong. Likewise not shown, there is normally somesuitable delivery facility for handling the stacked cartons which aredispatched from the stacker mechanism. One suitable form for suchapparatus would be a palletizing structure in which the tiers of cartonsare successively positioned adjacently to each other in linear rows andlaterally displaced by some suitable ram mechanism into groups of rowson a pallet for picking up or depositing in a truck or other deviceeither for storage or transport. Since these mechanisms do not form apart of the present invention, further description is here omitted. Thepresent invention relates instead to the stacking mechanism and themeans of control for the infeed such that no two cartons are in aposition to be handled at the same time or to interfere with each otheror with the operation of the stacking mechanism. There is illustrated,however, a control switch or equivalent device arranged along theconveyer beyond the stacker for the purpose of restoring operation ofthe stacker as a stack is discharged from the machine.

While the present invention consists of a very compact and simplemechanism for stacking cartons, it achieves its simplicity by means of areciprocating hoist within the stacking mechanism; and in such a hoistmechanism, to be operative without jamming or clogging, a control isnecessary limiting the arrival of packages into the machine to thoseintervals when the machine is ready to receive additional cartons forstacking. There is provided for this purpose a metering device andactuating means therefor which releases cartons from the abutment 15upon the occurrence of conditions within the stacker which permit thestacker hoist to operate in the normal fashion.

The operation of the infeed control device according to a preferred formof this invention may be understood best by reference to FIGS. 1, 9 and10. There is shown an air cylinder designated AC1 mounted in anysuitable fashion as by base 23 mounted on the stacker housing adjacentthe conveyer channel. The air cylinder has a piston shaft 25 extendingfrom the forward end of the cylinder through a fitting such as 26enabling it to be stroked out toward the right, as shown in FIG. 10.Secured to the shaft end by threaded receiver 27 is a thrust plate 28parallel to channel 12 and vertically disposed with a right angledportion 29 forming a vertical transverse arresting face in channel 12.

As illustrated in FIGS. 9 and 10, the plate member 28 and 29 is adaptedto be moved laterally across the conveyer upon the actuating of AC1; andwhen AC1 is not actuated, the rest position places the face 28 in linewith the conveyer panel 13 so that a carton may come directly againstthe leading face of pedestal 40 at the position indicated as abutment15. The outstroke of AC1 is sufficient, when properly adjusted, toadvance thrust plate 28 to alignment with the pedestal portion 15' fromwhich posi tion conveyer belt 17 can transport the carton into thestacking well. A carton disposed against the abutment 15 is indicated bythe numeral 18 in its ready position. When AC1 is actuated, the stackingmechanism accepts the carton for stacking, since it is displaced into aline of movement directly into the well as shown at 18. Any furtherarriving carton, when it reaches a position to contact arresting face29, will be there held and may be referred to as a waiting carton 18",in which position it remains until AC1 is stroked in, thus permittingthe carton to move into the position ready for release.

The release of a carton from its position 18 to position 18' iscontrolled by the air cylinder AC1, which may generally be operated by aconventional solenoid control on an air valve leading from a suitableair pressure supply, not here illustrated. This control is electricallyoperated in most cases as a matter of convenience, although other meansof operating the cylinder may optionally be selected for the samepurpose.

Control of AC1 is effected by means of switches LS1 and LS3b. LS1 isindicated at 31 as a conventional limit switch having normally opencontacts arranged in series with LS3b for the actuation of the AC1outstroking solenoid. Switch LS1 is mounted as by a raised flange fittedwith slotted mounting holes and screws adjustably secured to the leadingface of one pedestal 40, such that the switch is in its operatedposition whenever a carton 18 is urged into positon against the abutment15 by motion of the conveyer belt. The switch preferably is fitted withan operating spindle 33 bearing actuating arm 34 and a re turn spring35, there being a suitable termination at the end of the actuating arm34 such as roller 36 for engaging a carton as it approaches abutment 15.Rotation of spindle 33 actuates normally open contacts within the switchand provides for sufficient overtravel. Actuating arm 34 is fullydisplaced from the channel 13 contact upon the arrival of a carton butwill not reopen the switch contacts until the carton has been laterallydisplaced into position 18 for acceptance in the stacking well.

Upon actuation of AC1 piston 25 and thrust plate 28 move the carton 18beyond the range of arm 34. This, however, does not stroke the piston infor the reason that the air cylinder solenoid control is single actingand requires the closing of a further circuit to actuate the solenoidcontrolling AC1 (in) to retract pistom 25. This is accomplished throughthe connection to a further limit switch LS4 later to be described inconnection with the hoist cycle. Closing of LS4 and actuation of AC1(in) again aligns the plate 28 with the conveyer wall 13, and waitingcarton 18" advances to the ready position at 18, thereby reclosing thecontacts of LS1. As will later be noted, the switch contacts LS3b areopen during the cycling of the hoist, and AC1 is not stroked out by theclosing of LS1 except when the hoist is at rest since the hoist mustcommence its upward stroke before LS4 is closed, at which time LS3!) isalready opened. LS3!) remains open until the hoist returns to thereceive position.

When a further arriving carton 19, which may be following closely behindcarton 18, reaches arresting plate 29, the arriving carton is therearrested. It will be noted that this carton cannot actuate LS1 until AC1is stroked in but is restrained against the arresting face 29. Tosupport the arresting face against the forward urging of a carton on theconveyer, there is provided a J tracking roller 39 disposed to movealong the face of the pedestal 40 in the vicinity of the abutmentsupported by brackets 37 and 38, each attached to thrust plate 28.Tracking roller 39 maintains spacing between plate 28 and pedestal 40for smooth operation.

The infeed control mechanism hereinbefore described operates to controlthe feeding of cartons into the stacker mechanism. The construction andoperation of the stacker mechanism will thus be understood by referencefirst to FIGS. 3 and 4 in which are shown two views of like pedestalsindicated generally at 40 placed on opposite sides of the conveyer 10 atthe stacking position. Pedestals 40 contain like hoisting and holdingmeans except that the controls and the motive power are normallydisposed within one of the units 40. The pedestals each consist of floorbased supports indicated genorally at with internal supporting structurenot shown in detail and a surrounding housing formed, for example, ofsheet metal or plastic as at 44 so as to entirely enclose the unit withthe exception of ports as necessary for operations to be described. Thecompanion pedestals thus have inwardly facing walls adjustably spaced toaccommodate cases or cartons passing therebetween, disposed parallel andin a position to receive cartons substantially in contact with inwardfacing walls. The pedestals are preferably supported directly on thefloor adjacent to the conveyer and are normally detachably secured tothe conveyer therebeneath such that the pedestals may not move withrespect to each other or the conveyer during operation. With eachpedestal and on opposite interior walls thereof are hoist guides 45 and46 secured to the housing wall and supporting structure, convenientlyformed of T-bar stock having the flat faces secured to these oppositewalls of the housing, respectively, and having the flanges thereofinwardly extending in a position to receive hoist slides 47 and 48,preferably disposed in pairs of which the members are at upper and lowerextremities of a reciprocating hoist structure generally indicated at50.

Vertical hoist frame members 51 and 52, which bear hoist slides 47 and48, are rigidly secured to cross members 53 and 54, providing a rigidstructure for the hoist 50.

The hoist unit so constructed is arranged to be moved vertically by anamount which is adjustable according to the size of the carton to behoisted. Accordingly, hoist guides 45 and 46 are sufficiently long toaccommodate motion of the hoist and hoist slides 47 and 48 therealongfor a distance substantially greater than the height of the largestcarton which will be stacked by the mechanism.

As shown in FIGS. 3 and 4, the hoist is in its lowermost position atwhich member 54 barely clears the fioor. The member 54 of each hoistsupports a pair of transverse members which extend inwardly toward thecompanion pedestal and are joined by a rigidly secured bar at theextremities to form a lifting arm 55 arranged generally parallel to theinward facing walls and extending suificiently into the channel 12 tounderlie cartons moved along the conveyer belt 17. Arms 55 mayconveniently be of angle iron with a fiat surface upward. At thislocation the channel bottom is removed to accommodate the arms 55, andthe wall 44 is slotted to permit vertical reciprocation of the supportstherefor. The arms 55 extend sufficiently into channel 12 so that whenmoved vertically they pass by the holding fingers later to be described,which extend thereinto by a lesser amount. On each arm 55 is a rigidlyattached stop 56 arranged to arrest the passage of a carton in channel12 when arms 55 are in the receive position shown at 55 of FIGURE 4. Thestops 56 are arranged on a line perpendicular to the direction of travelof the belt and constitute means for orienting packages exactly withinthe stacking channel or well.

Cir

Ordinarily the pedestals will be closely adjusted to the width of thecartons then being stacked, thereby to cause proper lateral placement onthe belt 17 over arms 57. Close spacing of pedestals 40 assures angularorientation of adequate precision for most purposes. Nevertheless, theremay be circumstances in which narrower cartons are stacked withoutreadjusting lateral spacing of the pedestals, and some misalignmentmight thereby result. A further feature of construction avoids thisresult. In the event one edge of an arriving carton is ahead of theopposite leading edge it will first strike one stop 56 (which is inposition 56 when a cart-on is received) after which the carton will becarried along until the opposite edge strikes the corresponding stop 56at the other side of the channel, pivoting about its support point onthe belt 17. By this means each arriving carton is exactly positionedabove arms 55 and each succeeding carton thereafter arriving will beplaced in identical stacking position. Since it is a function of thelifting arms to raise these cartons in succession placing each onebeneath a previously elevated carton, except in the case of the firstcarton of a stack, all cartons so arranged have aligned leading edgesand with the lateral edges correspondingly aligned.

The hoist 50, here generally referred to in the singula-r, consists oftwo like frames, one in each pedestal. These hoist members are caused tocoact as a single hoist by means of simultaneous operation of a pair oflifting arms 57, each of which reciprocatingly rotates with a supportingshaft 58, journaled in a pair of bearings 59, one bearing being on each,pedestal 40 and secured to the housing 44 thereof and to the reinforcingstructure therein by means of bolts as at 61. Both arms 57 of the pairare keyed to shaft 58 such that they operate simultaneously through thesame are of rotation there about. Arms 57 are each connected to thecorresponding hoist structure by means of connecting rods 62, eachsecured to an arm 57 and to the hoist member by bearings 63 and 64,respectively.

At the top of one of the pedestals 40 there is mounted a drive motor 65,preferably supplied with a magnetic brake 66 or other means for bringingthe motor quickly to a stop at the termination of any phase of itsoperation. The motor operates through a gear box 67 to rotate a drivedisc 68 suitably supported in the pedestal for rotation about an axisparallel to shaft 58 to operate the hoist mechanism and lift a stack ofcartons. Drive disc 68 carries a crank pin 69 to which connecting rod 71attaches for operation by crank pin 69. The opposite end of eachconnecting rod 71 connects to one of the arms 57 at bearing 72 which maybe adjustably located along the arm 57 at a distance from shaft 58 toaccommodate various heights of lift desired for the hoist. It is thusseen that when the motor operates, disc 68 is driven in rotation and arm57 is moved in arcuate reciprocation whereas the hoist 50 reciprocatesvertically between two positions determined by the adjustment along arms57 of the bearings 72.

By the structure provided the motor 65, operating drive disc 68,connecting rod 71, lifting arm 57, connecting rod 62 and hoist 50elevates the pair of arms 55, whenever a carton is placed thereon, to apredetermined height. This elevation is sufficient to bring the arms 55above the level of the top of a newly arriving carton coming into thestacking well. To hold the carton in the elevated position until afurther carton is placed thereunder holding fingers 73 and 74 arearranged one pair in each pedestal. Each such pair of holding fingers issupported on the structure of the pedestal adjacent to the inward facingwall and extendable through ports cut therein under control of thecycling mechanism to withdraw the fingers as cartons are lifted andinsert them at the top of the stroke so as to hold up each successivelyelevated carton. Thus, each successively arriving carton is stackedbeneath the carton previously elevated.

In order to release a completed stack from the elevated position thesupporting fingers must be prevented from re-entering the stacking wellduring the remainder of that lift cycle. The holding fingers arearranged and actuated so as to be positively inserted into the stackingwell at the appropriate time, and to be positively withdrawn from thestacking well, both when a new carton is elevated and when it is desiredto release a stack. The structure to provide this feature of theinvention includes bearings mounted on the frame within the pedestals atthe inward facing walls thereof, these bearings being designated 75 inFIG. 4, and supported in any convenient manner on the internal structuresupporting the walls 44. Bearings 75 carry shafts 76 supported forrotation therein. It is convenient generally to arrange one member of apair of bearings 75 in each pedestal at either end of a shaft 76.Rotatively attached to shaft 76 is a frame member 77 which may be formedof a pair of angle irons interconnected by a rigid plate serving as amovable base structure for mounting the finger mechanism. The framemember 77 has inwardly extending flanges carrying shafts 79 arrangedalong a common axis parallel to shaft 76 substantially therebelow on theframe 77 such that rotation of frame 77 about shaft 76 moves the framemember outwardly from its normal position next to the wall 44. Shafts'79 receive the holding fingers 73 and 74, as illustrated in FIG. 5.Each finger consists of an elongated member of substantially L-sectionhaving a horizontal portion 81 extending into the stacking well when inthe normal rest position and having a vertical portion at right anglesthereto extending downwardly from its junction with the horizontalportion 81 and into contact with the frame member 77 so as to maintainthe horizontal portion perpendicular to frame member 77 when in thenormal position. The shafts 79 support the fingers by bearings 78attached thereto near the junction between the horizontal portions 81and the vertical portions 82.

The holding fingers thus attached to the frame member 77 are actuatablefrom the normal position of the frame member 77 which is vertical andwhich extends the portions 81 into the stacking well with a horizontalattitude. The frame member is supported for arcuate reciprocating motionat shaft 76 whereby when the frame member 77 is displaced from itsvertical position, finger portions 81 are withdrawn from the stackingwell. Means for positively withdrawing or inserting each pair of fingersin the stacking well consists of an air cylinder designated AC2 whichmay be of the bellows type, one in each pedestal, attached to the frame77 by means of trunnions 84 supported by ears 85 which are rigidlyattached to the frame members 77 by bolts as at 86. A piston shaft 87,or other bellows actuated shaft for each air cylinder AC2, extends to abearing 88 which is supported by ears 89 secured to the inner wall ofthe stacking mechanism, preferably at the center thereof between theports 83 through which portions 81 of the holding fingers extend. Theair cylinder is of conventional design and is supplied with conventionalfittings at either end thereof for the admission of air pressure and itsrelease under control of a suitable control mechanism. Electricalcontrol mechanism for the cylinders AC2 is indicated generally at 80 andis of conventional design supplied as a part of the air cylinderassembly with separate connections for control of air pressure to strokethe piston out or in upon signal. Thus, each pedestal is identicallysupplied with an air cylinder AC2, and a control mechanism 86 suppliesair pressure from a suitable source not here shown. Actuation of the aircylinders either to stroke them in or out is controlled by electricallimit switches LS4 and LS5 operated by the rotation of the drive disc68, as later described. When the cylinder is stroked out by admission ofair to the right end thereof, as shown in FIG, 6, the piston togetherwith its mounting on frame 77 is arcuately moved to the right by thethrust of the rod 87 through its bearing 8% and support 89 against aninner wall of the pedestal. When the air pressure is released from theright end of the cylinder and pressure is admitted to the left end ofthe cylinder, the piston is stroked in and frame member 77 is pivotallyactuated to its normal position vertically depending from shaft 76. Aseach carton is elevated by the hoist past the fingers '73 and 74, theair cylinders AC2 are stroked in to insert the fingers beneath theelevated carton. Horizontal portions of the fingers shown at 81 thenextend into the stacking well by a distance somewhat less than thelifting arms 55 and, since the fingers are shorter than the arm 55, donot interfere with the return stroke of the lifting arm as it movesdownward to its original position, shown in FIG. 4. However, as a newlyarriving carton is elevated beneath the carton then resting on thefingers, these fingers are withdrawn by positive outstroking of AC2.

In order to avoid need for a precise timing of the cylinder stroke toalways release the supported cartons of varying sizes at the instant thenewly hoisted carton comes into bottom contact therewith it isconvenient to employ ratchet action inherent in the described mountingof the fingers by bearings 78 on shafts 79 on the frame 77. Thus, whilethe hoist is elevating a new carton beneath that already stacked abovethe fingers, these fiingers may be pushed aside in the event that thenewly hoisted carton contacts the lowermost stacked carton prior to thetime the fingers are fully withdrawn. When this occurs, the horizontalportions 81 are permitted to rotate upwardly about the shaft 79 to theextent necessary to permit the upward movement of the newly elevatedcarton, the ports 83 through which the fingers extend being elongatedupwardly by an amount suflicient to permit ratcheting retraction of thefingers therethrough. As illustrated in FIG. 6, the normal position ofthe vertical portion 82 of the fingers restrains rotation of the fingersabout the shaft 79 only in one direction such that the horizontalportions 81 may not be pushed below their horizontal position. Thedashed line showing of a finger upwardly rotated in FIG. 6 isillustrative of the ratcheting action permissible by rotation on shaft79. Unless the newly elevated carton contacts portion 81 of the fingerit will not be so rotated because of the distribution of weight on thefinger about the shaft 79. The fingers may thus be actuated either tothe inserted or to the withdrawn position, positively by AC2, but mayalso be retracted by virtue of the passage of a carton from beneath intocontact with cartons held thereon to permit a ratcheting action for theelevation of the newly elevated carton.

The structure also accomplishes the essential purpose of positiveretraction during the entire downstroke of the hoist whenever a stack iscompleted, to permit stack discharge since the circuit actuating AC2 tothe instroke is prevented from operating by the operation of a relay asthe stack is completed. Cylinder AC2 remains in its outward strokeposition until operation of the instroke control.

As best shown in FIG. 7, drive disc 68 has a lower dead-center positionfor crank pin 69 for which the hoist is in its lowermost position asdescribed in connection with FIG. 3. This is the stack dischargeposition of the hoist corresponding to the electrical diagram of FIG. 12rather than the position in which the stacking mechanism is ready toreceive an additional carton for stacking. It will be noted that limitswitch LS3 has a pair of normally closed contacts LS3a and a pair ofnormally open contacts LSFib. It is mounted on a structural plate behindthe drive disc by means of pins 92 extending both through the structuralplate 93 and the mounting plate on the switch LS3, each being providedwith slotted apertures for the pins such that LS3 may be adjusted inrotation and in radial position with respect to the axis of the drivedisc 6%. By this means fine adjustment for the operating position of LS3may be provided even though actuation therefor is by a cam or striker 95which is secured at the lower dead-center position for the disc 63. Cam95 serves as a striker for actuate lever 96 of LS3 which is preferablysupplied with a roller 97 in order to secure long life and reliableoperation of the switch. The roller 97 bears against the rim of the disc68 to rotate post 98 when the striker 95 thereon engages the roller 97.Roller 97 is shown displaced approximately thirty degrees from thedead-center position, so that LS3 would be actuated substantially pastthe dead center at which the hoist is at its bottom position. Thestriker is of sufiicient width to assure that the motor brake 66 bringsthe motor to a stop before roller 97 passes completely over striker 95.The normally closed contacts LS3a remain closed except when striker 95actuates lever 96. Opening of LS3a contacts cuts off the motor unless ashunt circuit therefor is provided (PCS), which will be presentlydescribed.

The function of the normally open contacts LS3b was described inconnection with AC1 and the infeed metering device. These contacts areclosed by actuation of the lever 96, and when series contacts LS1 areclosed, there is completed an actuation circuit from a power supply toAC1 to stroke it out, which outstroking thus cannot occur at any hoistposition except that indicated for actuation of lever 96.

When a carton is released by simultaneous actuation of LS1 and LSEb, thecarton moves into the stacking mechanism and approaches the stops at 56'and breaks a photocell beam to close a photocell control switchconnected in shunt with contacts LS3a previously described. Aphotoelectric cell and actuating light beam may be ar ranged so that thelight source is in one pedestal while the receiving cell is in the otherpedestal. The pedestals thus may be moved apart or closer togetherwithout in any way affecting the functioning of the photocell control.This control is illustrated in FIGS. 1, 11 and 12 as consisting of thetwo parts designated PC and PCS whereof PC is a photo control unit ofconventional design energized from a suitable power supply in parallelwith other operative circuits, and includes a conventional light sourceand the circuitry for closing a pair of switch contacts PCS when thebeam is interrupted. There being no other cycling control element inseries with PC, it will operate to close the contacts PCS at any timewhen a carton is between the two pedestals at the level of the arrivingcarton. While this occurs during stack discharge cycles, LS3a is alreadyclosed and PCS does not start a new cycle. Photocell actuation to closenormally open contacts PCS avoids the ditiiculties inherent in movementof cartons both horizontally along the channel 12 and vertically in thestacking well, since no actual contact need be made with cartons.

The normally open contacts PCS and LS3a are in parallel connection fromthe power supply through the contacts of relay R2a (normally closed) toan actuating control for the motor 65 designated in FIG. 12 as D, andclosing either PCS or LS3a to operate the motor 65. LS7 is mounted inposition to be opened at the time when the drive disc 68 is in its lowerdead-center position whereby the circuit to the motor control D,normally completed through closed contacts LS3a, may be opened to stopthe motor, even though relay R2 is still energized, before it cycles toa position where LS3a opens (receive position). For this purpose LS7 ismounted on plate 93 as by mounting plate 99 and clamping bolts 101passing through adjusting slots, as in the case of LS3. It has actuatingarm 103 and actuating roller 104 thereon mounted for rotation aboutactuating post 102. It is arranged for actuation of the contacts intotheir open position at the time striker 95 is in its lowermost positionat lower dead center.

Also under control of the hoist cycle there are limit switches forelectrical control for finger actuation frame 77 for stroking out or in,as shown in FIG. 7, by a striker 105 at the top of disc 68 when 69 is atbottom dead center. A limit switch LS4 is mounted on structural plate 93by means of mounting plate 106 and clamping bolts 107 operating throughcrossed adjusting slots in plates 93 and 106. The switch LS4 is fixed toplate 106 and has actuating lever 108 and actuating roller 109 arrangedto rotate switch post 111 whenever striker 105 Contacts roller 109,after which it returns by spring action to its normally open position.It has contacts which are closed by operation of lever 108 as roller 109rides over striker 105, to supply power to AC2 control and apply airpressure to the outer end of AC2, stroking both cylinders outsimultaneously. LS4 has normally open contacts which serve to releasethe next carton waiting as at 18". By arranging the actuation of LS4some what later in cycle than LS3, LS4 remains unactuated except for ashort interval after de-actuation of LS3 as a carton begins to behoisted in the stacking well.

A similar limit switch LS5 is fixed on mounting plate 112 and adjustablysecured to plate 93 by bolts 113 as in the mounting of LS4. LS5 isactuated by lever 1 14, roller 115 and post 116, and is mounted to causeroller L15 to contact striker as the hoist reaches top dead center,thereby operating control 80 to admit air to AC2 stroking them in atthat time. Power is applied to control 80 through normally open contactsof LS5 when actuated except when further control contacts in seriestherewith are opened during .the stack discharge cycle.

During each lifting cycle as the hoist reaches its lowest position afterelevating a carton, or lowering a stack of cartons upon the conveyer,the motion of the hoist is terminated by the opening of LS7, except thatthis is permitted to happen only during lowering of the completed stackbecause normally closed cont-acts R2a are in shunt circuit across theLS7 contacts, and provides control by LS7 only when R2a is opened tocause stack discharge.

The discharge cycle is initiated by any hoist cycle which elevates a topcarton of the stack to a level predetermined to limit the stack height.A limit switch LS6 is mounted at an adjustable position near the top ofthe stacker on one pedestal with an actuating lever, of any well-knowntype permitting a degree of over-travel, disposed with-in the well to becontacted as the hoist elevates a completed stack to the predeterminedposition. Normally open contacts LS6 are then closed and normally closedcontacts R2a are opened to place LS7 in control of the hoist motor aspreviously described. To lower the stack the fingers 73, 74 areprevented from entering the well below a completed stack by breaking thecircuit to AC2 (in). To keep the fingers retracted after LS6 isde-actuated, relay R2 is provided with connections to a power supply foractuation when LS6 closes. R2 has contacts R2a in shunt with LS7, asbefore noted, nonmally closed contacts R2!) in series with LS5 and AC2(in), and normally open contacts R2c shunting LS6 to form. a keep-aliveor lock-in circuit for R2, effective upon the opening of LS6 as thestack is lowered. Contacts R2!) prevent insertion of the fingers by deactivat-in g the LS5 control of AC2 (in) and R2a holds open the shuntfor LS7 making the latter effective in stopping the motor at itslowermost position to allow the stack .to pass from the machine overstops 56.

To re-establish control of the mechanism by the cycle controls a limitswitch LS8 is disposed beside channel 12 at the outfced section of thestacking well having an actuate lever indicated in FIG. 1 at 117 andnormally closed contacts thereof interposed in the power circuit to R2via LS6. Upon actuation of 1.17 as a stack passes from the well, LS8opens to break the circuit to R2, thereby restoring nonmal cyclingcontrols as before actuation of LS6, since control LS7 which stopped themotor at bottom dead center is then shunted by R20: to cycle the hoistmotor on to the point of breaking its supply circuit as LS3a reopens.LSS closes upon the passage of the stack therebeyond and the mechanismis then ready for a new cycle conditioned upon the presence of a cartonagainst stop .15.

, It sometimes becomes desirable to terminate a stacking operation priorto the completion of the stack, and to dischange the partially formedstack. This is accomplished by means of the discharge button andcontacts carried by R2. As previously noted, operation of the dischargebutton closes R20 to lock R2 in the operated condition. Further contactsR2d, are connected in parallel with PCS and LS3a and in series witheither RZa or LS7 to maintain motion of .the hoist mechanism through D.Contacts RZe are connected in series with LS4 and AC2 (out), and thesecontacts do not affect the operation of the mechanism previouslydescribed except that the finn gers may not be inserted in the well tointercept a descending partial stack of cartons during a downstroke ofthe hoist, when R2 is actuated. R212 and R2e are normally closedcontacts permitting operation of AC2 either out or in as LS4 or LS5 isactuated. Contacts R2c and Kid are norm-ally open, and close only as R2is actuated. A further set of normally open contacts R2.) is connected,one contact to the junction of R22 and AC2 (out) at one end and theother to the junction of LS5 and RZb, to provide control of the holdingfingers during a manual discharge cycle, causing the holding fingers toremain effective until the hoist reaches top dead-center position as inthe normal stack discharge operation.

To briefly restate the automatic operation of the stacker, we may startwith the stacker moved through a discharge cycle and returned to itsreceive position such that the stacking well is empty and the liftingarms are in position beneath the channel 12 but above their lowermostposition such that the stop 56 on each arm extends upward into thischannel. Switch LS3 is actuated by striker 95 to close L331? and ope-nLS3a. The parallel-connected switch contacts PCS are also open, therebyto cut oii the motor actuator D. LS1 may then or thereafter be actuatedby arrival of a carton against abutment 15, to close LS1. All othermotion limiting switches are in their rest or normal condition. LS6 andLS7 are thus closed to complete the circuit through D whenever eitherLS3a or PCS is closed.

Starting with the machine at the receive position, a carton is placed inthe infeed section, the conveyer transport-s it along the channel untilit reaches the abutment and is held there. Since LS1 contacts arearranged for actuation when the arm 34 is urged in the direction ofmotion of the cartons on the conveyer, they will be closed when thecarton arrives at 15. Since LS3!) is already closed, LS1 now completesthe circuit from the power supply to the actuating solenoid for the aircylinder AC1, thereby causing the air cylinder to be stroked out. Plate28 attached to AC1 is thrust against the forward portion of the cartonurging it laterally into the channel to pass abutment 15, and theconveyer is enabled to carry the accepted carton into the stacker.Contacts LS1 open to break the circuit to the outstroke solenoid forAC1.

The first carton is then moved into the stacker sufficiently to operatephotocell PC and close contacts PCS in shunt with open switch LS3astarting the hoist motor by operation of motor control D. Upon operationot the hoist motor the striker 95 leaves its engagement with theactuating arm for LS3, thereby closing LS3a to maintain operation of themotor and opening LS3!) to prevent a new metering action at the infeedmechanism regardless of actuation of LS1. The positioning of thephotocell is such that the hoist does not elevate the carton until suchtime as it has passed along the channel into contact with stops 55, oneon each hoist arm. A second carton approaching the abutment is stoppedby plate 29 before it reaches LS1 which cannot be actuated until LS4returns AC1 to its position. Thereupon carton 18" moves to the positionat 18.

The drive disc 68 attached to the hoist motor rotates to close limitswitch LS4 to cause the hold fingers to be withdrawn from the verticalchannel in which the carton is moving, before the package has progressedmuch above the channel. This finger retraction is achieved by operationof AC2 (out). When the drive disc has reached its degree rotationposition, the striker 95 engages the actuator of the switch LS5, therebyenergizing the instroke solenoid control for AC2. LS5 is actuated atabout top dead center for the hoist, and the hold fingers are insertedbeneath the carton to prevent its return to the conveyer channel. Themotor continues lowering the lift arms until the drive disc is at thebottom dead-center position at which time LS7 is actuated, but theactuation of LS7 does not become etTective to break the circuit to themotor control D because of the shunt path through R2a. The motorcontinues to operate until the striker 9S actuates LS3 to open LS3a, atwhich time it is again stopped in the receive position. This permits afurther metering action to occur with the release of a second carton atthe abutment and its transport along the conveyer into the stacker forre-actuation of the motor as PCS contacts close. A further lift cyclecommences, as before, the second carton rising exactly beneath the firstcarton and thrusting thereagainst at approximately the time LS4 againoperates to stroke the hold fingers out of their holding position.Thereafter the lifting arms raise both cartons until the lower one is inthe position occupied by the previous one, and the hold fingers areagain inserted, this time beneath the second carton. The hoist motorcontinues its operation as before, again picking up a carton as it isreleased thereto by the metering device. The third carton takes itsposition beneath the other two raising them thereabove in a stackedarray.

When, for example, five cartons are to be stacked one above the other,the fifth carton is raised to the first elevated position of the firstcarton, and the first carton stacked thereabove extends to a position inthe stacking well which is set as the limit of stack height, the cartonstriking the actuating lever for LS6. As the contacts of LS6 close, acircuit is made through normally closed LS8 to relay R2 which is lockedin to hold open the circuit for air cylinders AC2 (in). In this Waycompletion of the stack prevents the reinsertion of the holding fingersbeneath the bottom member of the stack, and the entire stack isthereupon lowered to the conveyer. The lifting arms pass suflicientlybeneath the horizontal channel so that the stops 56 permit passage ofthe stack along the conveyer to the exit opening of the stacker.

As the hoist reaches the bottom of its travel, LS7 opens to stop themotor which remains stopped until such time as RZa recloses. Switch LS8,mounted adjacent the exit of the stacker, is actuated as the cartonsemerge from the stacker to open its contacts, thereby interrupting thecircuit to R through its hold-in contacts R20. R2 thereupon returns tonormal condition, R2c being opened thereby and R2a and R2b being closed.LS8 recloses as the stack passes. The hoist motor cycles on to itsreceive position as R2a closes. A complete discharge cycle has nowoccurred, and all switches are in the same position as at the beginningof the operation described. It is noted that all switches are in theirnormal or unactuated positions just prior to the reopening of LS3a whenno carton is at abutment 15.

While additional circuits may be employed for further control of thestacker, they do not enter into the stacking operation as describedexcept that this stacking operation may be interrupted automatically forsuch purposes as assuring that the exiting stacks are properly disposedof. The stacking mechanism described could, for example, be employedwith a palletizing device having a further limit switch controlling themotor control device to prevent the operation of the hoist if the stackdisposal area is filled. Since various auxiliary devices do not form apart of the present invention, they are not further described.

It will also be understood that while certain of the switch combinationsare described as separate switches, they may cooperate in point of timeand could be combined in a single unit when suitably actuated. It islikewise evident that the relay having thereon several sets of contactscould be replaced by an equivalent structure employing more than onerelay, but with substantially the same switch closing and openingfunctions, suitably synchronized in time as indicated. Similarly LS3controlling the instroke and the outstroke of AC2 could be replaced byseparate switches actuated at substantially the same time so long asboth the instroke and the outstroke solenoids were not simultaneouslyactuatable. R1 is shown in series with RB. START and RB. STOP to providefor locking-in power connections after P.B. START is released. Aself-locking RB. START button might be used in lieu of the arrangementshown.

It will also be understood that while limit switches have been describedand illustrated as simple expedients for the closing of circuits inprescribed cycling relationship to each other, equivalent structurecould be employed by anyone skilled in the art employing relays or othersimilar devices closing contacts according to the time relationshipdescribed. Similarly, it is a matter of choice whether air cylinders areactuated by solenoids as described or by some other suitable means underautomatic control of the switching arrangement selected. Employment ofthe components and mechanism as illustrated and described provides arugged unit which is highly reliable in operation and adaptable to readyadjustment for stacking of cartons of various sizes, either by simpleadjustment of the channel width as the pedestals are positioned or bythe changing of the position of such switches such as LS6 and of thestroke of the lifting lever 57 by adjustment of the position ofattachment of the connecting rod 71 thereto. It will be observed thatthe driving disc carrying the rotary moving end of the connecting roddescribes a constant circle, for example employing a circular diameterand stroke of eight inches, thus providing a motion of the liftingplatform variable up to about eighteen inches.

It may also be observed that additional circuitry may be used such as apush-button mechanism for starting the operation under manual controlwith a further pushbutton for stopping the action until such time as itis manually restarted. Likewise, a push-button actuating device might bedesired for bypassing the complete stacking of a stack of cartons. Thismight occur, for example, at the end of a day or when for some otherreasons it might be desired to terminate the operation before a stack iscompleted. By this means a partial stack could be discharged withoutotherwise affecting the readiness of the mechanism to resume theautomatic stacking opera tion. Such manual controls are diagrammaticallyillustrated in FIG. 12. In this way a completely versatile unit isprovided which is adaptable for manual operation at critical points orunder unusual circumstances with a return to automatic operationwhenever desired. The structure described and illustrated is exceedinglycompact and operates with a conveyor which need not extend more thanfour inches above the floor upon which it is mounted, and requires nooperating pit. It is, therefore, transportable and may be set up at anyplace desired; either at the place where the cartons are loaded or at astorage facility where it is desired to stack cartons in a massivearray. Since the two pedestals are floor mounted on either side of aconveyer and are connected together only by the shaft whichinterconnects the hoist arms to assure their simultaneous operation, theunit is readily assembled astride a suitable conveyer at which it isdesired to employ stacking operations. The only other requiredconnection between the two pedestals of the stacker is the air hose forthe simultaneous operation of one of the two air cylinders AC2, andelectrical controls for the air cylinder which is not at the pedestalhaving the motor and other control circuits. An additional. feature isthe employment of an infeed metering mechanism which is easily andquickly attached to a channel merely by the placement in the channelinfeed section both the olfset channel guide and the abutment with themetering switch and actuating cylinder AC1 attached. Limit switch LS8may be secured by an arm to one of the pedestals, being disposed foractuation as the stacks emerge from the machine.

While the invention has been described with respect to a particularembodiment, it will be understood that many modifications of theoperative principles are contemplated within the scope of the appendedclaims.

What I claim is:

1. Box stacker mechanism comprising in combination: a pair of framemembers defining a stacking well, a through-feeding conveyer having aload transporting belt moving through said well from an infeed stationto a loading station therebeyond, means at said. infeed stationpreventing boxes transported by said belt from entering said well untilindividually released, reciprocatingly cycled means supported by saidframe members for elevating each box entering said well sufiiciently toclear the next entering box, paired finger means one in each said membercontrollably insertable in said well to restrain downward motion ofelevated boxes, control means actuated by the lift means to positivelyretract said finger means during elevation of boxes and to reinsert saidfinger means prior to a return stroke thereof for causing successivelyelevated boxes to be bottom-stacked on the finger means, second controlmeans actuated by a predetermined stack elevation to prevent the nextsucceeding said reinsertion of the fingers for causing stacked boxes insaid well to be returned to said belt for movement to said loadingstation, third control means responsive to completion of eachreciprocating cycle for releasing a box in said infeed station, fourthcontrol means delaying completion of a cycle during which said secondcontrol means is actuated until said stacked boxes: have reached saidloading station, and stop means attached to said elevating means forarresting boxes on said conveyer belt when said cycle is completed, saidstop means being re tracted below said conveyer during said delay of acycle.

2. In the stacker mechanism of claim 1, first said means including afixed transverse abutment and conveyer guide means directing each boxtransported therealong into arrested position against said abutment.

3. In the stacker mechanism of claim 2, said third control meansincluding a powered transverse thrust arm laterally disposed before saidabutment and actuated in response to presence of a box against saidabutment when said cycle is completed.

4. In the stacker mechanism of claim 1, said stop means comprising apair of stops disposed on either side of said conveyer beltperpendicular to the line of motion thereof whereby transported boxesare individually reoriented in fixed position.

5. In a carton stacking device including a throughfeeding conveyer andan elevator structure straddling said conveyer and having lift armsnormally at the conveyer level reciprocatively cycled above and belowsaid level from the elevator to elevate above said conveyer each cartonentering the structure, a lateral offset in said conveyer adjacent theentrance of said elevator disposed to stop cartons passing therealong,means electrically actuated when said lift arms are at said level tomechanically release a carton at said offset being electricallyde-actuated upon said release, object sensing means electricallyinitiating a reciprocating lift cycle of the arms upon entrance of 21released carton into the elevator, control means on said arms stoppingeach entering carton in predetermined orientation thereon, meansactuated at the top of each lifting cycle to insert retaining fingersbeneath the carton last elevated, means actuated during the first ofeach succeeding lifting cycle withdrawing said fingers from theelevation path and causing any cartons already supported in elevation tobe stacked upon the carton then in the lifting cycle, control meansoperative at predetermined stack height to prevent said insertion of thefingers during the instant cycle to cause the stacked cartons to belowered upon said conveyer, means interrupting the cycle while said armsare below said level after lowering said stacked cartons, and meansresponsive to exit passage of said stacked cartons for completing saidcycle.

6. A carton stacking machine comprising, spaced vertical support membersdefining lateral stacking Well limits, a horizontal conveyer operativebetween said members forming infeed and outfeed sections, pairedelevator arms one carried by each of said support members, hoist meansfor cycling said arms from a receiving position to upper and lower limitpositions, paired holding supports one carried by each said supportmember exteriorly of said elevator means and within said well limits,closed gate means stopping cartons in said inteed section, meansoperative while said elevator means are in said receiving position forreleasing one carton at said gate means, means operative upon saidrelease reclosing said gate means, means operative as said cartonarrives between said members to actuate a cycle of said hoist means,means actuated by operation of the hoist means withdrawing said holdingsupports from said well during upward motion of said arms, meansoperative at said upper limit position reinserting said holding supportsin the stacking well below last said limit position, stack release meansoperative during a selected downward motion of said arms preventingoperation of last said means, thereby to lower stacked cartons upon saidconveyer, means on said arms for preventing passage of a carton while insaid receiving position and permitting passage thereof while in saidlower limit position, means arresting said cycle in said lower limitposition on operation of stack release, and means operative when saidstack release means is not operated for returning said arms to saidreceiving position.

7. In a stacker mechanism having a vertical stacking well above acontinuously moving conveyer, driven rotary cam means, elevator meansreciprocatingly operated by said cam means operative in said well toelevate each carton received therein, means controlled by said cam meansfor holding each last elevated carton at the upper limit of elevatoroperation, means controlled by said cam means for withdrawing from saidWell the holding means as successive cartons are raised therein, meansreleasing cartons when stacked to predetermined height being operativeto withdraw until the stack is released the holding means from the wellwhen said height of stack is reached, and gate means admitting onecarton to the stacker at the end of each elevator reciprocation,comprising an infeed channel section offset from said Well to arrestcartons arriving thereat and means for laterally displacing cartons insaid channel section to alignment with said well.

8. In a carton stacker including a conveyer having infeed and outfeedsections adapted to transport single cartons thereto and stacked cartonstherefrom, having hoist means including arms continuously cycleable froma position for receiving a carton thereon to an elevated position abovethe next entering carton, thence to a position below said receivingposition and finally to said receiving position for elevating to uniformheight each carton upon passage from the inieed section, optical sensingmeans for detecting the passage of the carton from said inteed section,powered shaft means operatively supporting crank means for driving saidarms and operative in response to actuation of said optical means, cammeans synchronously rotatable with said shaft means to actuate a powercircuit only when said arms are in said receiving position, a meteringdevice in said infeed section comprising offset means on said conveyerarranged to displace cartons to one side of the conveyer, an abutment atsaid side constructed to engage and hold a first corner of a transportedcarton and arranged at least one carton length toward said stacker fromthe termination of said displacing means, whereby a carton may berepositioned to pass said abutment, a control switch having actuatemeans arranged for actuation by a carton contacting said abutmentwhenever said power circuit is actuated, electromechanically operatedpusher means responsive to the presence of said hoist means in itsreceive position and to the actuation of said actuate means extendableto reposition said corner of said carton, and means controlled byrotation of said cam device for retracting said pusher means at adelayed position in each said cycle, said pusher means being effectivewhen extended to prevent further operation of said switch until thehoist has been operated.

9. In a carton stacking machine, a continuously operating conveyer meansdefining a horizontal pathway through said machine, a frame defining avertical stacking channel above said means, paired vertical lifting armsdisposed one at each side of said channel, paired arresting stops one oneach said arm arranged when in said pathway to define a stackingposition for a carton transported by the conveyer means, lift cyclingmeans responsive to arrival of each carton at said stops for elevatingsaid arms to a height exceeding one carton height and return through abottom position to an initial position with said stops in said pathway,means operatively responsive to completion of the lifting portion ofsaid cycle for inserting holding fingers beneath said carton in itslifted position, metering means at said horizontal pathway preventingcartons from entering said machine during said cycle and releasing onecarton upon completion of said cycle, means operative upon successiveelevations of cartons to withdraw said holding fingers from said channelthereby depositing previously lifted cartons upon the carton lifted bysaid arms during instant said cycle, control means operativelyresponsive to accumulation of a predetermined stack elevation forinterrupting during instant said cycle the operation of said insertingmeans thereby to lower the stack to the conveyer, means interruptingsaid cycle at said bottom position sufficiently beneath said initialposition to maintain said stops below said pathway thereby to permitexit of cartons lowered on the conveyer means, and means thereuponcausing completion of said cycle.

References Cited by the Examiner UNITED STATES PATENTS 1,862,603 6/1932McNaught 187-29 1,998,842 4/1935 Mosley 198-34 X 2,184,701 12/1939Kriechbaum et al. 318-467 X 2,857,040 10/1958 Campbell 214-62 2,924,0512/1960 More.

2,993,315 7/1961 Verrinder 214-62 2,995,273 8/1961 Hageline.

3,037,645 6/1962 Simpkins 214-62 3,038,615 6/1962 Roth 214-62 3,039,6246/1962 Campbell 214-62 3,053,402 9/1962 Russell 214-62 GERALD M.FORLENZA, Primary Examiner.

HUGG O. SCHULZ, Examiner.

1. BOX STACKER MECHANISM COMPRISING IN COMBINATION: A PAIR OF FRAMEMEMBERS DEFINING A STACKING WELL, A THROUGH-FEEDING CONVEYOR HAVING ALOAD TRANSPORTING BELT MOVING THROUGH SAID WELL FROM AN INFEED STATIONTO A LOADING STATION THEREBEYOND, MEANS AT SAID INFEED STATIONPREVENTING BOXES TRANSPORTED BY SAID BELT FROM ENTERING SAID WELL UNTILINDIVIDUALLY RELEASED, RECIPROCATINGLY CYCLED MEANS SUPPORTED BY SAIDFRAME MEMBERS FOR ELEVATING EACH BOX ENTERING SAID WELL SUFFICIENTLY TOCLEAR THE NEXT ENTERING BOX, PAIRED FINGER MEANS ONE IN EACH SAID MEMBERCONTROLLABLY INSERTABLE IN SAID WELL TO RESTRAIN DOWNWARD MOTION OFELEVATED BOXES, CONTROL MEANS ACTUATED BY THE LIFT MEANS TO POSITIVELYRETRACT SAID FINGER MEANS DURING ELEVATION OF BOXES AND TO REINSERT SAIDFINGER MEANS PRIOR TO A RETURN STROKE THEREOF FOR CAUSING SUCCESSIVELYELEVATED BOXES TO BE BOTTOM-STACKED ON THE FINGER MEANS, SECOND CONTROLMEANS ACTUATED BY A PREDETERMINED STACK ELEVATION TO PREVENT THE NEXTSUCCEEDING SAID REINSERTION OF THE FINERS FOR CAUSING STACKED BOXED INSAID WELL TO BE RETURNED TO SAID BELT FOR MOVEMENT TO SAID LOADINGSTATION, THIRD CONTROL MEANS RESPONSIVE TO COMPLETION OF EACHRECIPROCATING CYCLE FOR RELEASING A BOX IN SAID INFEED STATION, FOURTHCONTROL MEANS DELAYING COMPLETION OF A CYCLE DURING WHICH SAID SECONDCONTROL MENS IS ACTUATED UNTIL SAID STACKED BOXES HAVE REACHED SAIDLOADING STATION, AND STOP MEANS ATTACHED TO SAID ELEVATING MEANS FORARRESTING BOXES ON SAID CONVEYOR BELT WHEN SAID CYCLE IS COMPLETED, SAIDSTOP MEANS BEING RETRACTED BELOW SAID CONVEYOR DURING SAID DELAY OF ACYCLE.